HP XP P9500 Storage - Manual (Page 13)

Requirement Item
Maximum number of pairs decreases if LUSE volumes are used.
Consistency groups • You can configure up to 256 consistency groups in a storage system, including BC,
BC Z, Fast Snap (FS), and Snapshot (SS) consistency groups.
Note: BC, BC Z, FS, and SS pairs cannot co-exist in the same consistency group.
•
You can define up to 8,192 BC pairs in a consistency group.
Note: LUSE volumes that contain n LDEVs should be counted as n volumes.
For more information, see the HP XP P9000 Provisioning for Open Systems User Guide.
•
A number (0–FF) is assigned to each consistency group. You specify a consistency
group number when you create pairs. If you do not specify a number, the storage
system automatically assigns it.
- Consistency group numbers 00 to 7F (or 0 to 127) that you can use for BC, BC Z,
FS, and SS. Consistency group numbers 80 to FF (or 128 to 255) are exclusively used
for FS and SS.
License capacity requirements
The total capacity of pair volumes must be less than the maximum volume capacity licensed to you.
After operations begin, you should be aware of capacity requirements in order to keep volumes’
total size within purchased capacity.
•
P-VOLs, S-VOLs, and volumes are reserved for use as S-VOLs must have licensed capacity.
•
SS P-VOLs and pool volumes require the BC license capacity.
•
If you are using a volume for multiple purposes, the capacity of the volume is counted only
once. You do not need to multiply the capacity by the number of purposes for which it is used.
•
If you are using a Thin Provisioning volume as a BC P-VOL or S-VOL (or as a reserved volume),
the capacity of the Thin Provisioning pool allocated to the volume is added to the BC license
capacity. The reason is because Thin Provisioning volumes are not updated in real time. As
a result, some write requests may cause excess data, which is saved in the pool.
When your BC volumes exceed license capacity, you are allowed to use the volumes for additional
30 days. After that, you cannot perform BC operations except to delete pairs.
For more information, see the HP XP P9000 Remote Web Console User Guide.
Planning pair volumes
You must create volumes for P-VOLs and S-VOLs prior to creating pairs. For more information about
the system requirements for pair volumes, see
“System requirements” (page 12) . Also, you can use
the following options:
•
Before creating a pair, you can reserve a volume as an S-VOL. This ensures that an I/O does
not occur in the reserved volume before creating the pair. You can only use reserved volumes
as S-VOLs.
•
If you use , you can place a group of pairs in a consistency group. Using the consistency
group, you can perform pair operations on all the pairs in the group at the same time, including
consistency-group pair-split operations.
For more information about setting up consistency groups and performing pair operations,
see the HP XP P9000 RAID Manager User Guide.
Planning number of pairs
You can calculate the number of system resources required for a BC pair. With this information
you can calculate the maximum number of pairs allowed on your system.
License capacity requirements 13